Radio retransmission is widely used with portable radio systems. It is well known to relay communication between radio frequency units using Time Division Duplexing (TDD). For example, U.S. Pat. No. 6,342,777 issued to Takahashi on Jan. 29, 2002 discloses a TDD portable telephone relay device for use with a radio base station and a portable telephone terminal within a building. The disclosed system provides a TDD relay device that is wired to a base station for relaying a radio telephone channel between the base station and a portable phone located within an electrical-signal-insensitive region in the building. This retransmission, however, is accomplished in a cellular environment in a full-duplex TDD mode and may not meet the mobility requirements of certain communication systems.
Radio retransmission using a half duplex radio may be accomplished through several known methods. For example, in U.S. Pat. No. 5,442,803 issued to Furuya on Aug. 15, 1995 a half duplex radio communication system is disclosed having a plurality of radios and two base stations for relaying communications between two of the radios each of which is in communication with one of the base stations. The disclosed system assigns channels in a communication network for half duplex radio communications between the two radios via the two base stations collectively serving as a repeater station. This system, however, utilizes channel assignment rather than TDD to achieve a radio retransmission. Retransmission in half duplex radios may also be accomplished with two radios operatively cabled together. One radio operates as a receive radio and sends its received signal via the cable to the second radio which then rebroadcasts the signal. Although this method accomplishes single radio retransmission, there are several problems with this and other prior methods.
For example, soldiers in the field may wish to travel as light as possible. However, if a group desires to use the retransmission feature in present half duplex systems, they are required to carry two sets of radio equipment (radios, batteries, antennas) as well as cable to link together the two radios. It should also be noted that most radios fielded by soldiers are half duplex rather than full duplex. This is due to the cumbersome nature of current full duplex systems. Thus, the overhead of current half duplex systems is both costly and burdensome. In addition to equipment problems, users may also have to cope with electrical issues. A physical distance may be required between the radios to avoid interference when using two half duplex radios to perform retransmission. The physical distance must also be accompanied by a difference in frequency. If the transmitting half duplex radio were to rebroadcast the signal at the same frequency, the received signal of the first radio may interfere with the transmission of the second radio. Undesirable harmonics may result from rebroadcasting the signal when using different frequencies. Another issue may arise with known half duplex radio retransmission systems in a secure transmission environment. When conducting secure radio retransmissions in present half duplex systems, users may field the retransmission radios and leave them unattended due to the cumbersome nature of the radios while performing their mission. Communications protocols or cryptographic information may be compromised in the event this retransmission equipment fell into the wrong hands. Thus, a need exists to create a more manageable and efficient half duplex radio retransmission system.
It is therefore an object of the present disclosure to obviate the deficiencies of the prior art and present a novel half duplex radio for facilitating communication between two remote terminals using TDD. Embodiments of the apparatus may comprise of a receiver means for receiving data from a remote transmitting terminal, a buffering means for storing the data and a transmitter means for transmitting the buffered data to a receiving terminal.
It is another object of the present disclosure to provide a novel method of retransmission of data and range extension of data using TDD in half duplex radios comprising the steps of transmitting the data from a first half or full duplex radio to a retransmission half duplex radio wherein the retransmission half duplex radio buffers the data and retransmits the buffered data to a second half or full duplex radio.
It is a further object of the present disclosure to provide a novel system of data retransmission system using TDD comprising a first half or full duplex radio that transmits data to a retransmission half duplex radio. The retransmission half duplex radio receives the transmitted data from the first radio, buffers the data and retransmits the data to a second half or full duplex radio.
It is also an object of the present disclosure to provide a novel method of channel conversion of communicated data using TDD comprising the steps of transmitting the data from a first half or full duplex radio to a retransmission half duplex radio wherein the retransmission radio scans at least two different channels until data is received from one of the at least two different channels. An embodiment of this method also includes receiving the data by the retransmission half duplex radio, buffering the data in the retransmission radio, transmitting the buffered data by the retransmission radio and receiving the transmitted buffered data by a second half or full duplex radio.
It is yet another object of the present invention to provide a novel system of channel conversion of communicated data using TDD where a first half or full duplex radio transmits data to a retransmission half duplex radio wherein the retransmission radio receives, buffers and retransmits the data to a second half or full duplex radio.